Embodiments herein generally relate to electrostatographic printers and copiers or reproduction machines, and more particularly, concerns a transfer assist blade assembly for contacting an image receiving sheet.
The process of transferring charged toner particles from an image bearing member (e.g. photoreceptor) to an image support substrate (e.g. copy sheet) is enabled by overcoming cohesive forces holding the toner particles to the image bearing member. The interface between the photoreceptor surface and image support substrate is not always optimal. Thus, problems may be caused in the transfer process when spaces or gaps exist between the developed image and the image support substrate. One aspect of the transfer process is focused on the application and maintenance of high intensity electrostatic fields in the transfer region for overcoming the cohesive forces acting on the toner particles as they rest on the photoreceptive member. Careful control of these electrostatic fields and other forces is required to induce the physical detachment and transfer-over of the charged toner particles without scattering or smearing of the developer material.
Alternatively, mechanical devices that force the image support substrate into intimate and substantially uniform contact with the image bearing surface have been incorporated into transfer systems. Various contact blade arrangements have been proposed for sweeping the backside of the image support substrate, with a constant force, at the entrance to the transfer region. However, deletions may occur using these methods, especially in duplex.
In some conventional transfer assist blade assemblies each segmented blade is actuated by a separate solenoid. In other conventional transfer assist blade assemblies as disclosed for example in U.S. Pat. No. 6,134,398, the complete disclosure of which is incorporated herein by reference, the engagement timing and the width adjustment of the segmented blades are under separate mechanical controls, and the blade width adjustment is separately controlled by a rack and pinion mechanism.